1. Field of the Invention
The present invention relates to an omnidirectional camera device for use with a surveillance camera or the like. More particularly, this invention relates to an omnidirectional camera device which is able to pickup not only images of objects in all directions but also only an image of an object in a specified range, thereby hindering the camera device from picking up useless images of extra objects.
2. Description of the Related Art
Heretofore, there is known an omnidirectional camera device capable of picking up images of objects existing in all directions.
FIG. 1 of the accompanying drawings shows such an omnidirectional camera device 10 capable of picking up images of objects in all directions. As shown in FIG. 1, this camera device 10 uses a rotationally-symmetric convex mirror 12, and is able to pick up images of objects in all directions (360xc2x0) incident on the convex mirror 12 by an image pickup means, e.g. a video camera 14.
If such omnidirectional camera device which is able to pick up images of objects in all directions is installed at a specified position in the room, we can almost catch all situations within the room as if we were at the actual room. Therefore, since a large number of image pickup means need not be installed at different positions within the same room, this camera device is very suitable for watching the inside of the room and the like.
The direction of objects to be picked up should be restricted, otherwise light incident on the convex mirror 12 will not be introduced into the video camera 14 efficiently. Moreover, when the omnidirectonal camera device 10 is installed near the window in the proximity of the ceiling as shown in FIG. 2, only images of objects in the front directions shown at least by an angular extent 74  are necessary video information, but images of objects in the directions shown by an angular extent xe2x88x92xcex8 are useless video information for a user. On the contrary, it is frequently observed that such useless video information might disturb the user.
It is an object of the present invention to provide an omnidirectonal camera device in which the aforementioned defects encountered with the prior art can be obviated.
It is another object of the present invention to provide an omnidirectional camera device capable of choosing necessary information and useless information by restricting a range in which light becomes incident on a convex mirror.
According to an aspect of the present invention, there is provided an omnidirectional camera device which is comprised of a rotationally-symmetric convex mirror fixedly attached to one end of a transparent tube assembly, an image pickup device disposed on the other end of the tube assembly in an opposing relation to the convex mirror and a cover assembly being disposed on the tube assembly so as to restrict an extent in which light becomes incident on the convex mirror.
According to the present invention, a shielding cover assembly is rotationally attached to the outside of the tube assembly, whereby an angular extent in which light becomes incident on the convex mirror can be restricted. The extent in which incident light should be shielded and the direction of incident light that should be shielded may be determined by adjusting the attachment position of the cover assembly.
Further, since incident light is shielded by the cover assembly, all undesired information may be eliminated. Hence, the omnidirectional camera system is able to reliably pick up images of objects existing in the necessary directions and necessary ranges.